Open Source Software (OSS) is software for which the source code is openly licensed and available for scrutiny, adaption and reuse. This resource aims to help in the process of choosing, adopting, using, developing and sharing OSS for reproducible research. It also considers open code that is not software in itself but is code that is again openly licensed and available for scrutiny, adaption and reuse and that helps others reproduce research results, for instance, workflows which can be scripts that enact various software to process data in a particular order, experiments described using recipes, or scripts run within a particular software environment to automate some data processing in that environment. This document aims to encourage researchers to use and develop OSS and open code and provides some guidance in doing this.